The present invention relates, in general, to semiconductors, and more particularly, to semiconductor processing techniques.
In the past, the semiconductor industry has formed electrical contacts on the backside of semiconductor wafers or semiconductor die. One technique for forming such contacts is to first grind the backside of the semiconductor wafer in order to thin or reduce the thickness of the semiconductor wafer. During the grinding operation active devices on the front side of the semiconductor wafer are covered by a protective tape for protection. After the grinding operation, the tape is removed. Thereafter, the back side of the semiconductor wafer is etched with hydrofluoric acid to prepare the surface for application of an electrical contact. A contact material is subsequently applied using successive depositions of titanium, nickel, and a gold-germanium alloy.
One problem with this method is contact peeling. Often, the contact does not adhere to the underlying semiconductor surface and the contacts often peel off the semiconductor surface. The peeling results in defective devices and increased manufacturing costs.
Accordingly, it is desirable to have a method of forming a contact that results in the contact adhering to the semiconductor surface.